I don't recall if that particular article has been linked before, but Scanning Electron Microscopy is a standard way to look at very small stuff and is periodically discussed in the forum. See HERE, for example.

Compared to optical techniques, SEM offers the advantage of much higher resolution and DOF, at the cost of high expense and often more elaborate specimen prep requirements. Also it makes pictures that start off as grayscale. Those nice colors you see in published SEM pictures were hand-tinted by a human, based on recognizing the morphology of features seen on the subject.

From a scientific perspective the Electron Micrographs are brilliant as they have seemingly unlimited depth of field and the resolution is superb however as a descriptive tool they tend to fall short in my opinion as the images they produce do not look like real living creatures. Thats just my opinion. Both systems have their place I guess.

I used SEM pictures in many cases, but as already mentioned in this thread they are originally monochrome images (although some false color can be added by automated processing, based on how the subject scatters electrons). It is legitimate to manually add coloring to make it easier to distinguish e.g. anatomical features, but coloring a SEM image to make it look like an optical macrograph is rather futile (in a scientific sense).

A further, important limitation of SEM imaging is that the subject is usually metal-sputtered. The resulting images are rich in surface detail but completely lack any transparency/translucency. Mirror reflections are also completely absent, so (optically) very shiny surfaces are rendered by a SEM as completely opaque, dull and featureless. All in all, an extremely useful scientific tool, but it should not be forgotten that this is a completely different technique from optical photomacro/micrography.

Of course, SEM imaging shines at resolutions that exceed those of optical imaging. Many older SEMs are unable to accommodate a field of view larger than a couple of mm, or require the specimen stage to be disassembled and reassembled at a higher distance from the objective, which usually allows a wider FOV but does not permit operation at high magnification. On a SEM I used several years ago, reassembling the stage for low magnification work and recalibrating the scope required close to half an hour. Modern machines are usually better in this respect._________________--ES

A further, important limitation of SEM imaging is that the subject is usually metal-sputtered. The resulting images are rich in surface detail but completely lack any transparency/translucency. Mirror reflections are also completely absent, so (optically) very shiny surfaces are rendered by a SEM as completely opaque, dull and featureless.

Some newer scopes do not require coatings. As discussed at http://en.wikipedia.org/wiki/Environmental_scanning_electron_microscope,
"The environmental scanning electron microscope or ESEM is a scanning electron microscope (SEM) that allows for the option of collecting electron micrographs of specimens that are "wet," uncoated, or both by allowing for a gaseous environment in the specimen chamber."

However, this does not resolve any of the issues mentioned by Enrico. SEM intrinsically works through interaction of electrons with the surface of a structure -- no coherent reflections and no significant penetration -- so shininess and transparency (to light) don't get rendered even by environmental SEMs.

Some directly comparable optical and SEM images with an uncoated specimen are shown HERE.

I would love to own a desktop SEM, but have not found one yet for less then about $80,000 US and then you need the other accessories like a critical point dryer, sputter coater etc. Best to take a course at a University and then rent the scope for about $100 per hour - and let the experts maintain the scopes.

The other problem is the Nikon and Joel SEMs for desktops only offer very low resolution digital images.

If I win the lottery one day I will buy one, but for now I have to rent one at the University I want to use one. I am still paying off my Zeiss Axioscope!

I recently met a fellow who has five in his garage, along with much associated equipment. They go wrong quite often, it seems. Only "about two" work at a time. None of them is modern, and they were all obtained for a tiny fraction of their original cost - scrap value really. I understand that they rapidly become uneconomic to run for commercial use._________________Chris R